1. Field of the Invention
Embodiments of the present invention relate to a secondary battery.
2. Description of the Related Art
In a secondary battery, when internal abnormality, such as over-charge, over-discharge or internal short-circuit, occurs to the battery, an electrolyte inside the battery may be decomposed, so that gases such as carbon dioxide or carbon monoxide are generated, resulting in an increase of an internal pressure of the battery. In this case, there is a risk of explosion or fire occurring to the secondary battery.
Therefore, the secondary battery is subjected to safety tests against over-discharge or forced discharge, and various thermal stability tests, including a high-temperature retention test, a thermal shock test and so on. In the thermal stability tests, explosion and fire of a battery is determined while allowing the battery to stand at various temperatures for several to several tens of minutes.